off method

void off (Listener listener)

Remove event listener from emitter. This will unsubscribe the caller from the emitter from any future events. Listener should be a valid instance.

Implementation

void off(Listener listener) {
  if (null == listener) {
    throw ArgumentError.notNull("listener");
  }

  // Check if the listner has a valid callback for cancelling the subscription.
  if (null != listener.cancel) {
    listener.cancel(); // Use the callback to cancel the subscription.
  }
}